A referendum concerning the reduction of the members of the New South Wales Legislative Assembly was put to voters on 16 December 1903, in conjunction with the 1903 federal election.

The referendum was conducted on the basis of optional preferential voting.

However, preferences were not counted, as an overwhelming majority voted to reduce the number of members to 90.

[1] The text of the question was:[2] As to what shall be the number of Members of the Legislative Assembly.

Parliament was recalled to decide how to give effect to the referendum,[5] and passed the Electorates Redistribution Act 1904 which provided the districts were to be determined by three electoral districts commissioners.